1. Field of the Invention
The present invention relates to a workpiece processing device for processing a wafer workpiece, on the front surface of which a circuit pattern is formed and a surface protection tape is adhered, integrated with a mount frame into one body by a dicing tape.
2. Description of the Related Art
In the field of manufacturing semiconductors, there is a tendency for large-sized wafers to be used year after year. Further, in order to enhance packing density, wafer thickness is reduced. In order to reduce the wafer thickness, back-grinding is conducted on the back surface of a semiconductor wafer. At the time of back-grinding, in order to protect a semiconductor element formed on the front surface of a wafer, a surface protection film is adhered to the front surface of the wafer.
After back-grinding is complete, the wafer is conveyed to a workpiece processing device. FIG. 5 is a view showing a workpiece processing device of the prior art disclosed in Japanese Patent Application No. 2006-35159. A wafer 20, on the front surface 21 of which a surface protective film 110 is adhered, is subjected to back-surface grinding by a back-grinder 1 as shown in FIG. 5 and conveyed to a workpiece processing device 100.
A dicing tape is adhered to the back surface of a wafer 20 in a dicing tape adhering unit 300, so that the wafer 20 can be integrated with a mount frame 36 into one body. After surplus dicing tape has been wound by a surplus dicing tape winding unit 400, the wafer 20 and the mount frame 36 are conveyed to a surface protection film peeling unit 500. The surface protection film 110 is peeled off the front surface 21 of the wafer 20 by a well-known method.
The wafer 20 is then conveyed to a stage 270a in the workpiece processing device 100 and subjected to UV irradiation processing and/or expansion processing. Next, character information previously formed on the front surface of the wafer 20 is read out by an optical reading device (not shown). A bar code corresponding to the thus read character information is adhered to the dicing tape between the wafer 20 and the mount frame 36 or adhered to the mount frame 36 itself. This bar code contains information necessary for dicing the wafer. Next, the wafer 20 is accommodated in a cassette 16 and conveyed to a dicing device (not shown) together with the cassette 16.
In the dicing device, the bar code previously described is read out by a bar code reader (not shown). According to the information of the bar code, the operating condition of the dicing device is automatically set.
In the workpiece processing device disclosed in Japanese Patent Application No. 2006-35159, after the surface protection film 110 has been peeled by the surface protection film peeling unit 500, the wafer 20 is conveyed to a table different from the table (not shown) used for the surface protection film peeling unit 500. The wafer 20 is then subjected to the bar code adhering processing.
Since the back surface 22 of the wafer 20 is ground as previously described, the thickness is reduced. Accordingly, when the table for supporting the wafer 20 (and the mount frame 36) is changed after the surface protection film 110 has been peeled, the dicing tape and/or wafer 20 slightly undulates. When the dicing tape and/or wafer 20 slightly undulates, it is impossible for the optical reading device to accurately read out the character information of the wafer. Accordingly, an error occurs when the character information on the wafer is read. Further, in the case where the bar code is adhered to the dicing tape 3 between the wafer 20 and the mount frame 36, it becomes difficult to adhere the bar code.
In this case, in the dicing step, which is an after-step, it is impossible to appropriately set the operating condition of the dicing device according to the bar code. As a result, yield is lowered or working time is delayed.
The present invention has been accomplished in view of the above circumstances. An object of the present invention is to provide a workpiece processing device capable of avoiding failures when adhering a bar code.